1. Field of the Invention
The present invention relates to an autoclave suitably used in cure-molding tires and, more particularly, to an autoclave capable of creating a uniform temperature distribution therein and a tire manufacturing method using such an autoclave.
2. Description of the Related Art
A curing process is known as one of the processes in a method for fabricating tires called retreaded tires. In the curing process, a base tire, which serves as the base of a tire, and tread rubber, which is to be bonded to the periphery of the base tire, are placed in a curing envelope (hereafter “envelope” also). Then the envelope is introduced into an autoclave with the pressure inside the envelope reduced. In this manner, the cushion rubber, which is a bonding layer placed between the base tire and the tread rubber, is cured, thereby integrating the two tire members together firmly.
The autoclave used in the curing process is a cylindrical pressurized chamber capable of holding therein a plurality of tire sets (base tire and tread rubber) placed in their respective curing envelopes. The cylindrical pressurized chamber has a heat source disposed at one end side thereof to heat the air inside the pressurized chamber, a fan disposed near the heat source to circulate the air heated by the heat source, and an airtight door openably disposed at the other end side in the lengthwise direction thereof.
Also, disposed on the inner wall surface of the pressurized chamber is a duct extending lengthwise along the pressurized chamber. The air heated by the heat source is sent into the duct by the fan, and the air passing through the duct is discharged on the side where the airtight door is provided on the side opposite from the fan.
Then the air discharged at the airtight door side runs into the wall surface of the airtight door and is sent back toward the fan side in the pressurized chamber. The air, as it flows, heats the plurality of tire sets held within the pressurized chamber before it reaches the heat source. Again the air is driven through the duct by the fan and discharged on the airtight door side.
In other words, the autoclave is of such construction that the plurality of tire sets held therein are heated as the air heated in a pressurized chamber is circulated in the lengthwise direction of the chamber. Also, the pressure within the pressurized chamber is maintained at about 6 to 8, for instance, and the curing of the base tires and tread rubbers inside the curing envelopes progresses as they are heated under the pressure.